PMID- 2492217
OWN - NLM
STAT- MEDLINE
DCOM- 19890307
LR  - 20181130
IS  - 0013-7227 (Print)
IS  - 0013-7227 (Linking)
VI  - 124
IP  - 2
DP  - 1989 Feb
TI  - The peak phase of the proestrous prolactin surge is blocked by either posterior 
      pituitary lobectomy or antisera to vasoactive intestinal peptide.
PG  - 1050-5
AB  - The proestrous surge of PRL could result from a decrease in dopamine, an increase 
      in PRL-releasing factor (PRF) or both. The objectives were to determine whether 
      PRF from the posterior pituitary regulates the proestrous PRL surge, and to 
      examine if there are interactions between PRF and vasoactive intestinal peptide 
      (VIP). Posterior pituitary lobectomy (LOBEX) and passive immunization against VIP 
      were employed. Adult cycling rats were subjected at 0900 h on proestrus to LOBEX 
      or sham surgery (SHAM) under short term anesthesia, and were injected iv at 1330 
      h with 0.75 ml anti-VIP serum or normal rabbit serum. Jugular blood was collected 
      hourly from 1400-2300 h and analyzed for PRL and LH by RIA. Oviductal ova were 
      examined on estrus. The rise in plasma PRL in normal rabbit serum-treated SHAM 
      rats was biphasic, with an early peak between 1500-1700 h and a lower plateau 
      between 1900-2100 h. This rise was similar in profile and magnitude to that seen 
      in intact rats. In contrast, LOBEX significantly attenuated the early peak, but 
      did not alter the plateau. Passive immunization against VIP of either SHAM or 
      LOBEX rats mimicked the effect of LOBEX alone on PRL release. Neither surgery nor 
      anti-VIP serum affected the profile of the LH surge which was sharp and 
      symmetrical, and all rats ovulated with 15-16 ova per rat. To determine whether 
      VIP is the posterior pituitary PRF, selected tissues removed on proestrus or 
      diestrus-1 were analyzed for VIP by RIA. VIP was undetectable (less than 20 
      pg/organ) in the posterior pituitary on either day examined. The contents of VIP 
      in the anterior pituitary, medial basal hypothalamus, and paraventricular nuclei 
      were unchanged between diestrus-1 and proestrus. CONCLUSIONS: The proestrous 
      surge of PRL consists of two components: an early peak and a late plateau. The 
      peak phase appears to be dependent on PRF input from the posterior pituitary. 
      This input might be regulated by VIP, and interactions between the two could 
      occur at the level of the hypothalamus, anterior pituitary, or both. The plateau 
      phase of the PRL surge is independent of the posterior pituitary and VIP, and 
      might involve hypothalamic dopamine.
FAU - Murai, I
AU  - Murai I
AD  - Department of Physiology and Biophysics, Indiana University School of Medicine, 
      Indianapolis 46223.
FAU - Reichlin, S
AU  - Reichlin S
FAU - Ben-Jonathan, N
AU  - Ben-Jonathan N
LA  - eng
GR  - DK-39551/DK/NIDDK NIH HHS/United States
GR  - HD-21135/HD/NICHD NIH HHS/United States
GR  - NS-13243/NS/NINDS NIH HHS/United States
GR  - etc.
PT  - Journal Article
PT  - Research Support, U.S. Gov't, P.H.S.
PL  - United States
TA  - Endocrinology
JT  - Endocrinology
JID - 0375040
RN  - 0 (Immune Sera)
RN  - 37221-79-7 (Vasoactive Intestinal Peptide)
RN  - 5Y5F15120W (Thyrotropin-Releasing Hormone)
RN  - 9002-62-4 (Prolactin)
SB  - IM
MH  - Animals
MH  - *Estrus
MH  - Female
MH  - *Immune Sera
MH  - Pituitary Gland, Posterior/*physiology
MH  - *Proestrus
MH  - Prolactin/blood/*metabolism
MH  - Rats
MH  - Rats, Inbred Strains
MH  - Reference Values
MH  - Thyrotropin-Releasing Hormone/immunology/physiology
MH  - Vasoactive Intestinal Peptide/immunology/*physiology
EDAT- 1989/02/01 00:00
MHDA- 1989/02/01 00:01
CRDT- 1989/02/01 00:00
PHST- 1989/02/01 00:00 [pubmed]
PHST- 1989/02/01 00:01 [medline]
PHST- 1989/02/01 00:00 [entrez]
AID - 10.1210/endo-124-2-1050 [doi]
PST - ppublish
SO  - Endocrinology. 1989 Feb;124(2):1050-5. doi: 10.1210/endo-124-2-1050.