Circadian Periodicity of Serum Prolactin Concentration in Man

Nokin, Jacques; Vekemans, Marcel; L’Hermite, Marc; Robyn, Claude

doi:10.1136/bmj.3.5826.561

Cited by 146 publications

(31 citation statements)

References 12 publications

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“…Our data show that GRF has no effect on PRL secre tion in short normal children: the slow de cline in PRL levels between 8.30 and 11 a.m. (fig. 3A) probably reflects the normal circa dian rhythm of the hormone [10,31], On the other hand, the higher PRL levels of the majority of the hypopituitary patients also showed a circadian rhythm that was similar to that of the normal children ( fig. 3B), except for a small increase in PRL occurring 15 min after the GRF injection.…”

Section: Discussionmentioning

confidence: 99%

Effect of Growth Hormone-Releasing Factor on Plasma Growth Hormone, Prolactin and Somatomedin C in Hypopituitary and Short Normal Children

Vliet

Bosson²,

Robyn

et al. 1985

Horm Res

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We studied the effect of a single intravenous bolus of 0.5 µg/kg of growth hormone-releasing factor (GRF) on plasma GH, prolactin (PRL) and somatomedin C (SMC) in 12 short normal children and 24 patients with severe GH deficiency (GHD), i.e. GH < 5 ng/ml after insulin and glucagon tolerance tests. GRF elicited an increase in plasma GH in both short normal and GHD children. The mean GH peak was lower in the GHD than in the short normal children (8.2 ± 2.5 vs. 39.2 ± 5.1 ng/ml, p < 0.001). In the GHD patients (but not in the short normals) there was a negative correlation between bone age and peak GH after GRF (r = -0.58, p < 0.005); GH peaks within the normal range were seen in 5 out of 8 GHD children with a bone age < 5 years. In the short normal children, GRF had no effect on plasma PRL, which decreased continuously between 8.30 and 11 a.m. (from 206 ± 22 to 86 ± 10 µU/ml, p < 0.005), a reflection of its circadian rhythm. In the majority of the GHD patients, PRL levels were higher than in the short normal children but had the same circadian rhythm, except that a slight increase in PRL was observed 15 min after GRF; this increase in PRL was seen both in children with isolated GHD and in those with multiple hormone deficiencies; it did occur in some GHD patients who had no GH response to GRF. Serum SMC did not change 24 h after GRF in the short normal children. We conclude that: (1) in short normal children: (a) the mean GH response to a single intravenous bolus of 0.5 µg/kg of GRF is similar to that reported in young adults and (b) GRF has no effect on PRL secretion; (2) in GHD patients: (a) normal GH responses to GRF are seen in patients with a bone age < 5 years and

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Section: Discussionmentioning

confidence: 99%

Effect of Growth Hormone-Releasing Factor on Plasma Growth Hormone, Prolactin and Somatomedin C in Hypopituitary and Short Normal Children

Vliet

Bosson²,

Robyn

et al. 1985

Horm Res

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“…Measurement of plasma hormone concentrations during sleep has proven to be especially important for hGH (29), LH (30), and follicle-stimulating hormone (FSH) during puberty (31) and most recently hPRL (32). In 1972, Nokin, Vekemans, L'Hermite, and Robyn (33) showed the episodicity of hPRL concentrations with peak values at 1 a.m. and 5 a.m. when sampling was carried out at 4-h intervals. Sassin, Frantz, Weitzman, and Kapen (32) showed the important role of sleep in the regulation of hPRL secretion in normal young adults of both sexes.…”

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confidence: 99%

Hypothalamic-Pituitary Function in Diverse Hyperprolactinemic States

Boyar¹,

Kapen²,

Finkelstein³

et al. 1974

J. Clin. Invest.

161

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A B S T R A C T Prolactin secretion in normal adults is characterized by periods of episodic secretion which increase in magnitude during sleep. In this study, we report the 24-h mean prolactin concentrations, prolactin secretory patterns, and associated pituitary hormone function in nine patients (seven women and two men) with hyperprolactinemia of diverse etiologies. Four of the women and one of the men had clinically demonstrable pituitary tumors, one boy had a hypothalamic tumor, and the three other women had "functional" hyperprolactinemia. The 24-h mean prolactin concentrations derived from averaging the 20-min interval samples for 24 h ranged from 28.6 to 1,220 ng/ml. The plasma prolactin patterns in these patients showed persistence of episodic secretion in all and loss of the normal sleepwake difference in plasma prolactin in seven of nine. Three of the patients with galactorrhea and comparable 24-h mean prolactin concentrations (58.3, 59.7, and 64.3 ng/ml) showed similar prolactin secretory patterns despite different etiologic mechanisms. Evaluation of the secretory patterns of luteinizing hormone (LH) in these patients showed loss of normal pulsatile LH release and a low 24-h mean LH concentration in the patient with the pituitary tumor, while the two patients without clinically demonstrable pituitary tumors ("post-pill" galactorrhea and "idiopathic" galactorrhea) showed normal LH secretory patterns and 24-h mean LH concentrations. The 24-h mean cortisol concentrations and secretory patterns were normal in five of the seven patients who had these parameters measured. The patient with the hypothalamic tumor had a low 24-h mean cortisol concentration and production rate and absent response to metyrapone. The patient with "idiopathic" galactorrhea had an elevated 24-h mean cortisol concentration but normal cortisol production rate and urinary 17-hydroxycorticoid excretion. Growth hormone secre-

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“…It rapidly became evident that, due to a plasmatic half-life of about 15 min, a circadian rhythm (Nokin et al, 1972) and the effect of stress (sometimes considerable) (Noel et al, 1972), the interpretation of an isolated prolactinemia value was hazardous. It was thus necessary to carry out dynamic tests to estimate the stimulation or inhibition of secretion ; these tests used either TRH (thyrotropin-releasing hormone), known to release prolactin (Bowers et al, 1973 ;Jacobs et al, 1971), or rye ergot derivatives such as bromocriptine which inhibits prolactin secretion (Besser et al, 1972 ;Del Pozo et al, 1972).…”

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confidence: 99%