Pituitary Control of the Ovine Corpus Luteum

Denamur, R; Martinet, J.; Short, R. V.

doi:10.1530/jrf.0.0320207

Cited by 86 publications

(40 citation statements)

References 14 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…4) Denamur (1968) showed that hypophysectomy soon after ovulation resulted in the formation of a histologically normal CL up to Day 12 of the cycle, but progesterone secretion was abnormal. It has also been suggested that the luteotrophin in sheep may be a combination of prolactin and LH (Denamur, Martinet & Short, 1973 …”

Section: Discussionmentioning

confidence: 99%

Progesterone Levels Following Treatment of Seasonally Anoestrous Ewes With Synthetic Lh-Releasing Hormone

Haresign¹,

Foster²,

Haynes³

et al. 1975

Reproduction

114

View full text Add to dashboard Cite

Summary. Plasma progesterone determinations were carried out on blood samples collected daily from Clun Forest ewes during the normal oestrous cycle and also after administration of LH-releasing hormone (LH-RH) during seasonal anoestrus.Levels of plasma progesterone at oestrus ranged from 0\m=.\1to 0\m=.\5 ng/ml and luteal phase levels from 3 to 6 ng/ml. Levels found during seasonal anoestrus were within the range of those observed at oestrus. Following treatment with LH-RH, there was an increase in the plasma LH level in all cases and ovulation occurred in twenty-three out of twenty-seven treated ewes. In the animals which ovulated, the plasma progesterone concentration either remained basal (eighteen animals) or rose to a lower level (<2 ng/ml) than that found during the luteal phase of the cycle.

show abstract

Section: Discussionmentioning

confidence: 99%

Progesterone Levels Following Treatment of Seasonally Anoestrous Ewes With Synthetic Lh-Releasing Hormone

Haresign¹,

Foster²,

Haynes³

et al. 1975

Reproduction

114

View full text Add to dashboard Cite

show abstract

“…Although the life span of the corpus luteum during non-pregnant cycles varies considerably among species, it is generally true that function is maintained by a low steady-state level of circulating gonadotropin, LH in particular. LH is the predominant luteotropin in the nonpregnant woman (24); LH and prolactin maximize luteal progesterone secretion in the sheep (25) and probably also the rat (26); the hamster CL is dependent upon a luteotropic complex consisting of FSH, LH, and prolactin (27,28). Even though serum LH and steroid levels do not indicate a dynamic "pushpull" relationship during the luteal phase, the continued presence of LH or LH and PRL is necessary for normal progesterone synthesis in both primates (23,24) and nonprimates (26,29).…”

Section: Luteotropic Controlmentioning

confidence: 99%

“…It is equally well known that prolactin is absolutely critical for maintenance of the CL in the rat, for example (30), but it is not steroidogenic in the acute sense in vivo (31) or in vitro (32). Yet PRL may somehow synergize with LH to maximize luteal progesterone secretion in vivo (25). Thus, the extent to which prolactin is luteotropic strictly in the structural vs. the steroidogenic sense and the mechanism(s) of its action are unclear (33).…”

Section: Luteotropic Controlmentioning

confidence: 99%

Basic mechanisms of ovarian endocrine function

Schomberg¹

1978

Environ Health Perspect

View full text Add to dashboard Cite

This review outlines the current understanding of ovarian endocrine development and regulation with both physiological and biochemical background to provide a framework applicable to problems concerning environmental agents and ovarian endocrine function. Two approaches are used. First, the endocrine regulation of foUicle development and corpus luteum function is considered in the classical sense, i.e., viewing these structures as gonadotropin-responsive units undergoing a programmed sequence of development and differentiation. Secondly, a relatively new area of ovarian physiology concerned with intra-ovarian regulation is explored, since this area holds potential for exploration of the direct effects of toxicological or environmental agents upon gonadal endocrine cells. Follicle DevelopmentGonadotropin-Independent and Dependent StagesThe stages of follicular maturation have been classified in a variety of ways by several different investigators, depending upon the degree of detail necessary (1, 2). For purposes of this discussion, distinction need only be made between the following: (1) the primordial follicle stage, characterized by an immature ovum surrounded by a single layer of flattened or disc-shaped granulosa cells; (2) the primary follicle stage, characterized by a transition in granulosa cell morphology to the cuboidal form followed by an increase in the number of granulosa cell layers (In the rat, oocyte growth is complete by the four-layer granulosa cell stage); and (3) Follicle development in most species, with the notable exception of the human (3), is thought to be independent of gonadotropic support up to the

show abstract

“…The effect on ovarian physiology is at several stages, including follicular maturation, steroidogenesis, ovulation, luteinization and corpus luteum function. Prolactin is part of the luteotropic complex in many species including rats, mice, pigs and sheep (Denamur et al, 1973), and may also be luteotrophic during the early stages of luteal formation in humans (McNatty et al, 1974).…”

Section: Introductionmentioning

confidence: 99%