Body Weight Changes and Serum Growth Hormone Comparative Assessment in Female Lactating Wistar Rats (Rattus norvegicus) Treated with Metoclopramide and Some Atypical Antipsychotics

Aims: The study was aimed at comparative evaluation of body weight changes and the serum growth hormone level in female lactating Wistar rats treated with normal saline, metoclopramide olanzapine and risperidone.

Study Design: A total of twenty (20) Female Wistar rats weighing between 140-180 g were used for the study. The study was an experimental study carried out on lactating rats. Treatment started three days after parturition. Two atypical antipsychotic drugs were administered orally and their effects compared to that of a normal control group and a positive control.

Methodology: Group I served as the control and was administered 2 ml/kg normal saline. Group II received metoclopramide (5 mg/kg b.w) while group III received olanzapine (5 mg/kg b.w) while group IV received risperidone (5 mg/kg b.w). Administration was carried out by oral gavage using an oral cannula, for the period of fourteen (14) days at 06:00 h daily. At the end of the experiment, blood samples were collected using a 5 ml syringe through cardiac puncture and the sera obtained was used for growth hormone analysis. The weight (g) of the experimental animals were recorded using a digital weighing balance at 06:00h for days 0, 3, 6, 9, 12 and 14.

Results: There was a significant increase in mean serum growth hormone concentration (P<0.05) in the metoclopramide treated group; (19.35±1.14 ng/ml) compared to normal control; (11.53±1.64 ng/ml), olanzapine treated; (11.28±0.35 ng/ml) and risperidone treated; (11.30±0.70 ng/ml). However, there was no statistically significant difference in the olanzapine and risperidone treated groups compared to the normal control (P> 0.05).There was no statistically significant difference (P> 0.05) observed in the body weight changes although at day 14, metoclopramide showed the highest increase (180±1.30 g) compared to the normal control (172±1.83 g), olanzapine (173±2.30 g) and risperidone (175±3.80 g).

Conclusion: Metoclopramide at a dose of 5 mg/kg significantly increases serum growth hormone level (ng/ml) compared to olanzapine and risperidone in female lactating Wistar rats, with a non-significant increase in body weight of the dams.