Evaluation of insulin sensitivity in hyperprolactinemic subjects by euglycemic hyperinsulinemic clamp technique

Abstract

The background and aim of the study is to evaluate insulin sensitivity in hyperprolactinemic subjects via euglycemic hyperinsulinemic clamp technique. Sixteen hyperprolactinemic subjects and 12 healthy subjects were included in the study. HOMA-B and HOMA-IR values of groups were calculated. Euglycemic hyperinsulinemic clamp technique was performed in both groups, and the M value of the groups was defined. Mann-Whitney U and chi-square tests were used in statistical analysis. Basal insulin level of hyperprolactinemic patients were higher than the control group (6.85 +/- 4.68; 3.66 +/- 0.88 microU/ml respectively; P < 0.05). Mean HOMA-IR and HOMA-B values of patients were higher than control group (1.49 +/- 1.30; 0.78 +/- 0.27 respectively; P = 0.02 and 136.28 +/- 72.53; 64.77 +/- 23.31, respectively, P < 0.001). M values of the patients were statistically lower than the control group (5.64 +/- 2.36; 7.05 +/- 1.62 kg/mg/min respectively; P < 0.05). (1) Hyperprolactinemic patients were more insulin resistant than control subjects. (2) Insulin resistance in hyperprolactinemic patients is not associated with obesity or anthropometric parameters such as fat content, waist circumference and BMI.

Bromocriptine-QR therapy for the management of type 2 diabetes mellitus: developmental basis and therapeutic profile summary

“…These elevated plasma prolactin levels are generally 2-4-fold greater than normal and do not constitute frank clinical hyperprolactinemia and would not generally even be assessed as elevated by clinical laboratory standards. However, this relatively elevated plasma prolactin level has been taken as an index of reduced dopaminergic tone at this time of day and several studies have associated high plasma prolactin levels with obesity and insulin resistance in man [150][151][152][153][154][155][156][157][158][159]. Therefore, available evidence in humans supports the tenet that a decreased circadian peak in central (hypothalamic) dopaminergic activity is coupled to the insulin-resistant state, much the same as is observed in other vertebrate animals.…”

Serum prolactin concentrations determine whether they improve or impair β‐cell function and insulin sensitivity in diabetic rats

“…In the present study, low-PRL did not affect insulin resistance in diabetic rats but high-PRL exacerbated it. Previous studies have shown that both obese and non-obese patients with hyperprolactinaemia have reduced insulin sensitivity [40,41]. In addition, hyperprolactinaemic non-obese female patients had a tendency to have higher serum insulin levels and β-cell function than the control subjects [41].…”

“…Previous studies have shown that both obese and non-obese patients with hyperprolactinaemia have reduced insulin sensitivity [40,41]. In addition, hyperprolactinaemic non-obese female patients had a tendency to have higher serum insulin levels and β-cell function than the control subjects [41]. In pituitary-grafted female rats, fasting serum glucose levels and area under the curve of insulin were higher than those in sham-operated rats, and area under the curve of insulin was positively correlated with serum PRL levels [42].…”

Effect of Cabergoline on Metabolism in Prolactinomas

“…Furthermore, PRL excess is reportedly associated with disorders of glucose metabolism according to evidence deriving from studies in rodents and humans [4,20,21,22,23,24,25]. Particularly in humans, both physiologic and pathologic PRL excess has been shown to reduce glucose tolerance and to induce hyperinsulinemia [26,27,28], also increasing the homeostatic model assessment (HOMA) index [29,30,31] and reducing the insulin sensitivity index (ISI₀) [32] in both obese and lean patients.…”