The Anterior Hypothalamic Nucleus produces parasympathetic responses such as reduced heart rate and enhanced activity of the gastrointestinal tract when stimulated. The Preoptic nucleus plays a role in regulating sex hormones, which in turn regulate reproductive cycles, such as the menstrual cycle in females. Cells in the preoptic area also aid in the control of heart rate, blood pressure and body temperature. The Anterior Pituitary secretes growth hormone, thyrotropin, corticotrophin, follicle stimulating hormone, luteinizing hormone, and prolactin. The Posterior Hypothalamic Nucleus produces sympathetic responses when stimulated, such as increasing heart rate and inhibiting gastrointestinal activity.
Lesions here produce hyperphagia and obesity.
The VMH has also been demonstrated to play some role in aggression. The Mammillary body is considered part of the hypothalamus and limbic system. It interacts with brain stem nuclei utilizing the mammillo-tegmental tract. The fornix represents its connections with the hippocampus. The mammillothalamic tract represents a prominent connection with the thalamus.