Effect of prolactin on urinary excretion and renal haemodynamics in conscious rats.

Abstract

SUMMARY1. Conscious rats received a saline infusion (5-8 ml. hr-') via a tail vein, for a 6 hr period. For the final 2 hr of this infusion period, prolactin (74 ,tg (100 g body wt.)-'. hr-1) was incorporated in the infusate. A control group of animals continued to receive saline alone.2. In the first hour of prolactin administration (in comparison with the control group), urine flow, sodium output and osmolal output were all significantly reduced (P < 0-02); there was also a reduction (P < 0-05) in renal plasma flow (p-aminohippurate clearance), but the filtration fraction did not alter. The changes in urinary excretion, and in renal haemodynamics, did not persist for the second hour of prolactin adminstration, but there was a sustained increase in body fluid volume.3. It is possible that altered renal haemodynamics are responsible for the reduced urinary water and solute excretion which occurs during acute prolactin administration.

Acute and chronic effects of progesterone and prolactin on renal function in the rat.

“…Moreover, g.f.r. has been seen to increase (Lockett, 1965;MacCallum et al 1975;Riley, Hagen & Stefaniak, 1978), decrease (Bliss & Lote, 1982) or remain unchanged (Lucci et al 1975;Wallin & Lee, 1976) following acute hormone treatment.…”

“…The results of the prolactin infusion studies add to the controversy surrounding a potential osmoregulatory role for prolactin in mammals. Whereas many workers have demonstrated an acute salt and water retaining action for the hormone (Lockett & Nail, 1965;Horrobin, Lloyd, Lipton, Burstyn, Durkin & Muiruri, 1971 ;Lucci et al 1975;Miller & Van Gemert, 1976;Wallin & Lee, 1976;Bliss & Lote, 1982), others have failed to show this (MacCallum, Simpson & Auld, 1975;Baumann & Loriaux, 1976;Berl, Brautbar, Ben-David, Czaczkes & Kleeman, 1976). Moreover, g.f.r.…”

Effects of vasoactive intestinal polypeptide (VIP) on renal function and plasma renin activity in the conscious rabbit.

“…Reflex sympathetic stimulation secondary to peripheral vasodilatation may produce renal vasoconstriction, but this seems unlikely since VIP-induced renin release is not blocked by propranolol (Calam et al 1982). Systemic VIP is known to raise plasma prolactin levels (Fahrenkrug & Emson, 1982) and in physiological concentrations, prolactin has been shown to reduce renal perfusion and increase renal vascular resistance (Bliss & Lote, 1982). In contrast, Porter et al (1980) have reported a rise in renal blood flow during intrarenal VIP infusion in anaesthetized dogs, but increased sympathetic tone during anaesthesia (Price, 1966) is likely to alter vascular reactivity to vasoactive substances such as VIP (Uddman et al 1981).…”

Neurotensin and antinatriuresis in the conscious rabbit

“…Therefore, it is conceivable that neurotensin alters dopaminergic activity peripherally and perhaps even centrally. It may influence sympathetic nervous function and release of other hormones such as prolactin (Brown & Vale, 1977), thus affecting UNaV, GFR and PRA (Bliss & Lote, 1982). Furthermore, neurotensin immunoreactivity has been demonstrated within renal peptidergic nerves (Forssmann, Hock & Metz, 1982) and neurotensin may act directly to alter intrarenal blood flow or tubular function.…”