FACILITATORY EFFECT OF OESTRADIOL ON LUTEINIZING HORMONE SECRETION FROM IMMATURE FEMALE RAT PITUITARIES IN VITRO

1976 ◽  
Vol 70 (1) ◽  
pp. 155-156 ◽  
Author(s):  
M. WILKINSON ◽  
D. DE ZIEGLER ◽  
K. B. RUF
Keyword(s):  
Luteinizing Hormone ◽  
Hormone Secretion ◽  
Facilitatory Effect ◽  
Female Rat ◽  
Luteinizing Hormone Secretion ◽  
Immature Female

FACILITATION OF LUTEINIZING HORMONE SECRETION IN THE FEMALE RAT BY PROGESTERONE

1972 ◽  
Vol 53 (1) ◽  
pp. 37-46 ◽  
Author(s):  
K. BROWN-GRANT ◽  
F. NAFTOLIN
Keyword(s):  
Luteinizing Hormone ◽  
Hormone Secretion ◽  
Facilitatory Effect ◽  
Female Rat ◽  
Luteinizing Hormone Secretion ◽  
Lh Secretion ◽  
Sustained Increase

SUMMARY Progesterone injected intramuscularly at 09.00 h on the day of prooestrus in the 4-day cycle of the rat decreased plasma luteinizing hormone (LH) concentration for 2 to 3 h, but by 5 h after injection had triggered an abrupt, premature, and sustained increase in LH secretion. Between 4 and 5 h after injection sufficient LH had been secreted to raise the plasma LH concentration to more than 20 ng/ml and to induce ovulation in the majority of rats. The facilitatory effect of progesterone on LH secretion could be prevented, or extinguished after it had begun, by the administration of sodium pentobarbitone. The effects observed after administration at the prooestrous stage of the cycle are compared with those seen after progesterone injection under other conditions.

COMPARISON OF FOLLICLE-STIMULATING HORMONE AND LUTEINIZING HORMONE SECRETION AFTER ELECTRICAL STIMULATION OF THE PREOPTIC PART OF THE HYPOTHALAMUS IN FEMALE RATS ANAESTHETIZED WITH ETHYL CARBAMATE OR SODIUM PENTOBARBITONE

1978 ◽  
Vol 78 (1) ◽  
pp. 151-152 ◽  
Author(s):  
R. G. DYER ◽  
M. B. TER HAAR ◽  
LINDA C. MAYES
Keyword(s):  
Electrical Stimulation ◽  
Luteinizing Hormone ◽  
Follicle Stimulating Hormone ◽  
Hormone Secretion ◽  
Control Process ◽  
Female Rats ◽  
Female Rat ◽  
Luteinizing Hormone Secretion ◽  
Stimulation Of ◽  
Stimulating Hormone

A.R.C. Institute of Animal Physiology, Babraham, Cambridge, CB2 4AT (Received 17 January 1978) For over 30 years, the method by which the brain regulates the secretion of gonadotrophic hormones has been studied by electrical stimulation of those parts of the central nervous system thought to be implicated in the control process. Much of the work has been performed on the female rat. In this species, anaesthetic doses of sodium pentobarbitone, administered immediately before the pro-oestrous 'critical period', block the preovulatory surge of luteinizing hormone (LH) for 24 h. The same treatment also reduces the early phase of the pro-oestrous secretion of follicle-stimulating hormone (FSH; Daane & Parlow, 1971). Electrical stimulation of the preoptic part of the hypothalamus can overcome this blocking effect and analysis of the optimum parameters required to restore normal secretion of gonadotrophins may give some insight into the endogenous process (e.g. Everett, 1965; Fink & Aiyer, 1974;

scholarly journals Galanin Enhancement of Gonadotropin-Releasing Hormone-Stimulated Luteinizing Hormone Secretion in Female Rats Is Estrogen Dependent

Endocrinology ◽  
2003 ◽  
Vol 144 (2) ◽  
pp. 484-490 ◽  
Author(s):  
Cynthia L. Splett ◽  
Joseph R. Scheffen ◽  
Joshua A. Desotelle ◽  
Vicky Plamann ◽  
Angela C. Bauer-Dantoin
Keyword(s):  
Luteinizing Hormone ◽  
Hormone Secretion ◽  
Gonadotropin Releasing Hormone ◽  
Gonadal Steroids ◽  
Female Rats ◽  
Luteinizing Hormone Secretion ◽  
Ovx Rats ◽  
Lh Secretion ◽  
Lines Of Evidence

The hypothalamic peptide GnRH is the primary neuroendocrine signal regulating pituitary LH in females. The neuropeptide galanin is cosecreted with GnRH from hypothalamic neurons, and in vitro studies have demonstrated that galanin can act at the level of the pituitary to directly stimulate LH secretion and also augment GnRH-stimulated LH secretion. Several lines of evidence have suggested that the hypophysiotropic effects of galanin are important for the generation of preovulatory LH surges. To determine whether the pituitary actions of galanin are enhanced by the preovulatory steroidal milieu, LH responses to galanin administration (with or without GnRH) were examined in: 1) ovariectomized (OVX); 2) OVX, estrogen (E)-primed; and 3) OVX, E- and progesterone-treated female rats. Results from the study indicate that galanin enhances GnRH-stimulated LH secretion only in the presence of E (in OVX, E-primed, or E- and progesterone-treated rats). Galanin alone does not directly stimulate LH secretion under any of the steroid conditions examined. In the absence of gonadal steroids (OVX rats), galanin inhibits GnRH-stimulated LH secretion. These findings suggest that the primary pituitary effect of galanin is to modulate GnRH-stimulated LH secretion, and that the potentiating effects of galanin occur only in the presence of E.

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