Biomaterial Database

Prolonged pulsatile administration of gonadotrophin-releasing hormone (GnRH) to fertile stallions. 1991

J F Roser, and J P Hughes

Department of Animal Science, College of Agricultural and Environmental Sciences, University of California, Davis 95616.

Hormonal effects of prolonged administration of gonadotrophin-releasing hormone (GnRH) were investigated in 7 fertile stallions in winter and summer. The stallions were divided into 4 groups so that 1 animal received 0.625 micrograms of GnRH and each of 2 animals received 1.25, 2.5 or 5.0 micrograms of GnRH subcutaneously every 30 min for 5 days. Daily blood samples were collected from 5 days before to 5 days after treatment for measurement of plasma concentrations of luteinizing hormone (LH), follicle stimulating hormone (FSH), testosterone (T) and oestrogen conjugates (EC). Five-minute blood samples were collected over a 4 h period prior to, and on the last day of, GnRH treatment in each season for analysis of pulsatile changes in plasma LH concentrations. Mean concentrations of LH and T prior to treatment were higher (P less than 0.05) in summer than winter, whereas plasma FSH and EC concentrations did not differ between seasons. Increasing the dose of GnRH appeared to increase plasma concentrations of LH, FSH and T above baseline in winter (P less than 0.05), whereas a significant effect was not observed in summer. Plasma EC concentrations were not affected by treatment in either season. In GnRH-treated stallions, plasma LH and T concentrations were positively correlated such that the profiles of these hormone concentrations appeared to change in a similar direction over time in winter (P less than 0.01) but not in summer. Plasma concentrations of FSH and EC were not correlated in either season. A positive correlation between plasma LH and FSH concentrations was detected in both winter (P less than 0.01) and summer (P less than 0.02). In contrast, changes in plasma LH and T and plasma FSH and EC concentrations were not correlated over time in either season in control stallions. A positive correlation between plasma LH and FSH concentrations in control stallions was observed in summer (P less than 0.03) but not in winter. Prior to treatment, pulse patterns of LH were similar in both seasons. Following administration of GnRH, irrespective of dose, pulse frequency increased (P less than 0.05) and pulse duration decreased (P less than 0.05) resulting in a decrease in the total amount of LH released per pulse (P less than 0.05) in winter only. Amplitude and interval were not affected by GnRH treatment in either season. The results of this study suggest that the pituitary gland and testes of fertile stallions are more responsive to administration of prolonged pulsatile GnRH in winter than in summer.

UI	MeSH Term	Description	Entries
D007986	Luteinizing Hormone	A major gonadotropin secreted by the adenohypophysis (PITUITARY GLAND, ANTERIOR). Luteinizing hormone regulates steroid production by the interstitial cells of the TESTIS and the OVARY. The preovulatory LUTEINIZING HORMONE surge in females induces OVULATION, and subsequent LUTEINIZATION of the follicle. LUTEINIZING HORMONE consists of two noncovalently linked subunits, alpha and beta. Within a species, the alpha subunit is common in the three pituitary glycoprotein hormones (TSH, LH and FSH), but the beta subunit is unique and confers its biological specificity.	ICSH (Interstitial Cell Stimulating Hormone),Interstitial Cell-Stimulating Hormone,LH (Luteinizing Hormone),Lutropin,Luteoziman,Luteozyman,Hormone, Interstitial Cell-Stimulating,Hormone, Luteinizing,Interstitial Cell Stimulating Hormone
D007987	Gonadotropin-Releasing Hormone	A decapeptide that stimulates the synthesis and secretion of both pituitary gonadotropins, LUTEINIZING HORMONE and FOLLICLE STIMULATING HORMONE. GnRH is produced by neurons in the septum PREOPTIC AREA of the HYPOTHALAMUS and released into the pituitary portal blood, leading to stimulation of GONADOTROPHS in the ANTERIOR PITUITARY GLAND.	FSH-Releasing Hormone,GnRH,Gonadoliberin,Gonadorelin,LH-FSH Releasing Hormone,LHRH,Luliberin,Luteinizing Hormone-Releasing Hormone,Cystorelin,Dirigestran,Factrel,Gn-RH,Gonadorelin Acetate,Gonadorelin Hydrochloride,Kryptocur,LFRH,LH-RH,LH-Releasing Hormone,LHFSH Releasing Hormone,LHFSHRH,FSH Releasing Hormone,Gonadotropin Releasing Hormone,LH FSH Releasing Hormone,LH Releasing Hormone,Luteinizing Hormone Releasing Hormone,Releasing Hormone, LHFSH
D008297	Male		Males
D004966	Estrogens, Conjugated (USP)	A pharmaceutical preparation containing a mixture of water-soluble, conjugated estrogens derived wholly or in part from URINE of pregnant mares or synthetically from ESTRONE and EQUILIN. It contains a sodium-salt mixture of estrone sulfate (52-62%) and equilin sulfate (22-30%) with a total of the two between 80-88%. Other concomitant conjugates include 17-alpha-dihydroequilin, 17-alpha-estradiol, and 17-beta-dihydroequilin. The potency of the preparation is expressed in terms of an equivalent quantity of sodium estrone sulfate.	Conjugated Equine Estrogen,Conjugated Estrogen,Estrogenic Substances, Conjugated,Progen,Carentil,Climarest,Climopax,Congest,Conjugated Equine Estrogens,Conjugated Estrogens,Dagynil,Estro-Feminal,Estrogenic Hormones, Conjugated,Estrogens, Conjugated,Femavit,Oestro-Feminal,Oestrofeminal,Prelestrin,Premarin,Presomen,Progens,Transannon,Conjugated Estrogenic Hormones,Conjugated Estrogenic Substances,Equine Estrogen, Conjugated,Equine Estrogens, Conjugated,Estro Feminal,Estrogen, Conjugated,Estrogen, Conjugated Equine,Oestro Feminal
D005298	Fertility	The capacity to conceive or to induce conception. It may refer to either the male or female.	Fecundity,Below Replacement Fertility,Differential Fertility,Fecundability,Fertility Determinants,Fertility Incentives,Fertility Preferences,Fertility, Below Replacement,Marital Fertility,Natural Fertility,Subfecundity,World Fertility Survey,Determinant, Fertility,Determinants, Fertility,Fertility Determinant,Fertility Incentive,Fertility Preference,Fertility Survey, World,Fertility Surveys, World,Fertility, Differential,Fertility, Marital,Fertility, Natural,Preference, Fertility,Preferences, Fertility,Survey, World Fertility,Surveys, World Fertility,World Fertility Surveys
D005640	Follicle Stimulating Hormone	A major gonadotropin secreted by the adenohypophysis (PITUITARY GLAND, ANTERIOR). Follicle-stimulating hormone stimulates GAMETOGENESIS and the supporting cells such as the ovarian GRANULOSA CELLS, the testicular SERTOLI CELLS, and LEYDIG CELLS. FSH consists of two noncovalently linked subunits, alpha and beta. Within a species, the alpha subunit is common in the three pituitary glycoprotein hormones (TSH, LH, and FSH), but the beta subunit is unique and confers its biological specificity.	FSH (Follicle Stimulating Hormone),Follicle-Stimulating Hormone,Follitropin
D006064	Gonadotropins, Equine	Gonadotropins secreted by the pituitary or the placenta in horses. This term generally refers to the gonadotropins found in the pregnant mare serum, a rich source of equine CHORIONIC GONADOTROPIN; LUTEINIZING HORMONE; and FOLLICLE STIMULATING HORMONE. Unlike that in humans, the equine LUTEINIZING HORMONE, BETA SUBUNIT is identical to the equine choronic gonadotropin, beta. Equine gonadotropins prepared from pregnant mare serum are used in reproductive studies.	Pregnant Mare Serum Gonadotropins,PMS Gonadotropins,PMSG (Gonadotropins),Equine Gonadotropins,Gonadotropins, PMS
D006065	Gonadotropins, Pituitary	Hormones secreted by the adenohypophysis (PITUITARY GLAND, ANTERIOR) that stimulate gonadal functions in both males and females. They include FOLLICLE STIMULATING HORMONE that stimulates germ cell maturation (OOGENESIS; SPERMATOGENESIS), and LUTEINIZING HORMONE that stimulates the production of sex steroids (ESTROGENS; PROGESTERONE; ANDROGENS).	Pituitary Gonadotropins
D006736	Horses	Large, hoofed mammals of the family EQUIDAE. Horses are active day and night with most of the day spent seeking and consuming food. Feeding peaks occur in the early morning and late afternoon, and there are several daily periods of rest.	Equus caballus,Equus przewalskii,Horse, Domestic,Domestic Horse,Domestic Horses,Horse,Horses, Domestic
D000818	Animals	Unicellular or multicellular, heterotrophic organisms, that have sensation and the power of voluntary movement. Under the older five kingdom paradigm, Animalia was one of the kingdoms. Under the modern three domain model, Animalia represents one of the many groups in the domain EUKARYOTA.	Animal,Metazoa,Animalia