alpha-Melanocyte-stimulating hormone during human perinatal life

Area of Science:

• Endocrinology
• Neonatal Physiology
• Neuroscience

Background:

• The human pituitary intermediate lobe's activity during the perinatal period is not fully understood.
• Alpha-melanocyte-stimulating hormone (MSH) is a key peptide hormone produced by this lobe.

Purpose of the Study:

• To investigate human pituitary intermediate lobe activity throughout the perinatal period.
• To measure plasma alpha-MSH immunoreactivity (IR) in newborns and analyze factors influencing its levels.

Main Methods:

• Plasma alpha-MSH IR was measured in 106 newborns at delivery and during the first week of life.
• Subjects were grouped by gestational age, mode of parturition, and antenatal health status.
• The three major forms of alpha-MSH (desacetyl, alpha-MSH, diacetyl) were analyzed.

Main Results:

• Plasma alpha-MSH IR progressively decreased from preterm to full-term neonates.
• Levels were higher in vaginally delivered infants compared to those born via Cesarean section, and stress-related deliveries showed higher MSH IR.
• Total alpha-MSH IR significantly decreased within 12 hours after birth in term newborns, reaching a plateau by the fourth postnatal day in premature infants.

Conclusions:

• Pituitary intermediate lobe secretion, indicated by alpha-MSH IR, decreases throughout the third trimester of pregnancy.
• Parturition-related stress stimulates alpha-MSH IR release.
• Pituitary intermediate lobe activity declines shortly after birth, though this process is slightly delayed in premature infants.